Heterogeneous ice nucleation induced by porous materials

冰粒的成核作用对云的形成和随后的降水起着重要作用，对大气化学、云物理学和地球气候都有影响。为了在天气预报和气候模式中量化和预测云的影响，必须以真实的方式描述冰粒子的形成。最重要的形成机制之一是浸没模式中的非均质冰成核，其中冰在浸没在水性液滴中的冰核（例如矿物尘埃颗粒）的表面处引发。在本研究中，我们将进行大量的浸没冷冻实验。我们将研究在大气中以气溶胶粒子形式出现的各种物质的冰成核活动。特别是，我们的目标是量化的温度和时间依赖性的冰核诱导它们。一个特别的重点将是对多孔材料引起的冰成核的系统研究。我们希望研究合成材料如中孔二氧化硅以及天然存在的材料如微孔沸石。

The nucleation of ice particles plays an important role for the formation of clouds and subsequent precipitation, with implications for atmospheric chemistry, cloud physics and Earth's climate. In order to quantify and predict the effects of clouds in weather forecast and climate.models, ice particle formation has to be described in a realistic manner. One of the most important fomiation mechanisms is heterogeneous ice nucleation in the immersion mode, in which ice is initiated at the surface of an ice nucleus - for example a mineral dust particle - immersed in an aqueous droplet. We will perform numerous immersion freezing experiments during this study. We will investigate the ice nucleation activity of various materials that occur in the form of aerosol particles in the atmosphere. In particular, we aim at quantifying the temperature and time dependence of the ice nucleation induced by them. A special focus will be on the systematic study of ice nucleation induced by porous materials. We want to investigate both, synthetic materials such as mesoporous silica as well as naturally occurring materials such as microporous zeolites.